The Ministry of Defence records conclude there is no proof of invasion by little green men - but they say it can't be ruled out either.
They show that a Dundee saucer-spotter reported red and white lights, followed by a solid beam of red light, coming through their curtains in August 2002.
In another letter to the MoD, an unnamed woman from Cults, near Aberdeen, describes two mysterious "UFOs" she spotted while on courses in St Andrews.
She claims to have seen one flying saucer in July 1997, but reported another sighting after returning to the same summer school the following year.
The MoD looked into a case following an article in a national newspaper in 1996, only to discover lights over Balmoral were RAF Harrier jets from Leuchars.
Other reports in 2002 and 2003 - newly released from the National Archives - show reports of a glowing white flashing light above St Andrews, a flashing "very bright" white ball in the skies over Leven, and an orange-red, cigar-shape over the Firth of Tay.
Three drifting "hanging silver rods" were seen over Kirkcaldy in September 2002, while a jumbo jet-sized "changing shape" with blue, green and red pulsating lights was seen in Coaltown of Balgonie.
A bright, oval object was also seen over Tibbermore and a bright, distant object, which moved from side to side, was seen at Dunkeld.
